Sparking plug



5 FISHER ET AL SPARRING PLUG Flled March 30 1920 qk S i Patented Aug.28, 1923.

STANLEY FISHER, '01 EALING, AND WINWOOD PRIDDEY, OF MARYLEBONE, LONDON,ENGLAND.

'sranxmo PLUG.

Application filed March 30, 1920. Serial No. 369,899.

new and useful Improvements in Sparking- Plugs, of which the followingis a specification.

This invention relates to sparking plugs of the kind. having the centralportion readily removable from the threaded base or outer portion forthe purpose of cleaning and adjusting the sparking points or ofsubstituting a new central portion for an old defective one but held inposition with sufiicient pressure to maintain a gas-tight joint bymeansof an adjustable member which is independent of or separate from theremovable central portion.

According to the present invention, the adjustable member is formed witha .slotted flange and may have interposed between it and the centralportion a retaining ring or the like. This ring or the central portionitself is formed with lugs or projections which engage in correspondingslots in the base portion of the plug and the slots in.

the flange of' the adjustable member are formed to correspond with theslots in the base portion of the plug. When these slots are caused tocoincide or register, the central portion consisting of the electrodesand insulator, together with the retaining ring when such is employedmay be removed from or inserted into the base portion of the plug as aseparate self-contained unit without detaching the adjustable member.The latter may be in the form of a cap connected to the base portion ofthe plug by screw threads or any other suitable joint. \Vhen theremovable central portion is inserted in place, a partial turn of thecap causes the flange ofthe latter topress downwards upon the retainingrinand exert pressure on the central portion or compressing a suitablyarranged washer or wasliers and making a gas-tight joint. 'In order tofacilitate the removal and re-insertion of the central portion a stopmaybe provided to ensure the slots are in register. g

In order that the said inventionmay be clearly understood and readilycarried into effect, the same will now be described more fully withreference to the accompanying drawings,'in which c Figure 1 is anelevation, and

Figure 2 a vertical section of the improved sparking plug.

Figure 3 is an elevation partly in section, and

Figure 4 a plan of the base portion of the plug that screws into theengine cylinder in the usual manner.

- Figure 5 is a vertical section and Figure 6 a plan of the retainingring.

Figure 7 is a vertical section, and

Figure 8 a plan of the locking member or cap.

Figure 9 is an elevation partly insection of the central portioncomprising the two electrodes, insulator and retaining ring.

Figure 10 shews in vertical section 'a modified form of the device, inwhich the negative electrode, instead of being in the form of a thimble,is a plain rod passing through the plug body and fitting tightly into ahole drilled in the part d.

Figure 11 is an elevation of a modified .rial such as orcelain, fusedquartz, mica and so forth. 0th electrodes are preferably tipped withnickel inthe neighbourhood of their sparking points. d isthe retainingring which is formed with two diametrically opposite vertical lugs 6.These parts,.a, b, c and d constitute the removable central portion. Thering d is shown cut away internally to allow the insulator 0 to have asmuch cooling surface in contact with the air as possible. f is the baseportion of'the sparking plug formed with vertical slots 9 correspondingto the lugs e. The portion, f, usual, has a standard thread at its lowerend for screwin into the cylinder of the engine and has t e usualhexagonal portion upon which a spanner may be used. is is the flangedcap. The up er end of the portion f is formed with an external squarescrew-thread h, for the reception of a similar thread on the cap kwhichwhen inplace presses upon the ring (1 This cap is has,

plug for inspection or repair.

1 compress-the washer n thus obtaining a gastight joint. A washer m isalso pressed be tween the ring d and the insulator 0.

o is a stop pin which is mounted in a hole in the base portion f andpressed upwards by' a spring 10 against an inclined 'face 0 on the capk. The cap 70 may be unscrewed until it is stopped by the verticalsurface or shoulder 1- on the cap coming against the pin 0. Then theslots 9 are in register with the 2 slots Z and the central portion maybe withsulator c.

drawn with the ring d. Any other suitable form of stop may be used forthis purpose.

The central electrode a is square in crosssection and fits in a squarehole in the in- Tt makes-a gas-tight joint at the packing s when the nutt is screwed down and cannot rotate when the terminal nut u istightened. up. V The electric conductor is gripped between the nuts tand u. The lower end of the said central electrode a is madeball-pointed so that any drops of oil which tom thereof instead ofbecoming corbonised between the sparking points. The

earthed electrode 6 is in the formof a thin being spun or pressed into asmall groove 0 in the insulator a or instead it may have a small inwardprotuberance suchas a depression made by a punch which protuberance fitsinto a shallow bayonet groove in the lower part of the insulator c. Theelectrode 5 has internally projecting parts at m which form its sparkingpoints and are of proper size to provide the requisite spark gap betweenthem and the central electrode.

Referring to Figure 10, in this modification the insulator c is made intwo parts 0 and c, the latter being added after placing the ring (Z inposition. ll 'he negative electrode 7) is a rod fitting tightly into ahole in the ring (Z. The cap is may be provided with a short laterallyextending handle 3 where preferred.

Referring to Figures 11 and '12. a ring 2 below the ring 03 is employedto secure the negative electrode 6, the latter fitting into a Lea ersperforation in a protuberance on the ring 2, and theinsulator beinggrooved to accommodate the" protuberance .on the ring and also the'part0f the rod which projects from the ring.

Various modifications may be made in the ternal lugs and separatedfrom'the central electrode by a number of mica wrappings. There are thenmore mica washers and the whole is firmly heldby the top nut.

Yet again, the cap is maybe externally screw-threaded and may screw intothe base portion f or again it may be secured thereto by means of abayonet or any other appropriate form of joint suitable for this purose.a

p The removable central portion of the sparking plug consistsessentially of the insulator the rin d and the two electrodes,

a b and'one o 'ect of the invention is to render thlS POItIOII simple,cheap and e sy to manufacture. In using thesparking p 11g,

the base portion f and the cap k do not require tobe detached in orderto remove thecentral portion for inspect-ion'or'repair.

What we claim and desire to secure by Letters Patent of the UnitedStates is may reach it Will tend-to drip from the bot- 1. In a sparkingplug for an internal combustion engine, a base attachable to the enginecylinder, a removable portion comprising an insulator, electrodes andprojecting lugs, a cap adjustably mounted on the said base and having aflange normally engaging the said projecting lugs, the said flange beingprovided with slots adapted to be brought into register with the saidprojectin lugs for'the purposes specified.

2. n a sparking plug for an internal combustion engine, a baseattachable to the engine cylinder, a removable portion comprising aninsulator, electrodes and a retaining ring having projecting lugs, a caadjustably mounted on the said base an having a flange normally engagingthe said projecting lugs, the said flange being provided with slotsadapted to be brought into register with the said projecting lugs forthe purposes specified.

3. In a sparking plug for an internal combustion engine, a baseattachableto the engine cylinder, a removable portion comprising aninsulator. electrodes, one of which electrodes is ball-pointed andprojecting lugs, a cap adjustably mounted on the said base and having aflange normally engaging the said projecting lugs, the said flange beinprovided with slots adapted to be brought into register with the saidprojecting lugs for the purposes specified.

4. In a sparking plug for an internal oombustion engine, a baseattachable to the engine cylinder, a removable portion comprising aninsulator, electrodes the earthed electrode being fitted to the innerend of the said removable portion and provided with an internallyprojecting part, and projecting lugs, a cap adjustably mounted on thesaid base and having a flange normally engaging the said projectinglugs, the said fiangebeiug provided with slots adapted to be broughtinto register with the said projecting lugs for the purposes specified.

5. In a sparking plug for an internal combustion engine, a baseattachable to the engine cylinder, a removable portion comprising aninsulator, electrodes and projecting lugs, a nut adjust-ably mounted onthe said base and having a part normally engaging the said projectinglugs, the said part being provided with slots-adapted to be brought intoregistration with the said projecting lugs for the purpose specified.

STANLEY FISHER. WINWOOD PRIDDEY.

